#include "yocto/hashing/md5.hpp"
#include <cstring>

namespace yocto
{

	namespace hashing
	{
		namespace RFC1321
		{
			/* Constants for MD5Transform routine.
			*/



#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

			static const uint8_t PADDING[64] =
			{
				0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
			};


			/* F, G, H and I are basic MD5 functions.
			*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

			/* ROTATE_LEFT rotates x left n bits.
			*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

			/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
			Rotation is separate from addition to prevent recomputation.
			*/
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
				}

#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
				}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
				}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
				}

			/* Encodes input (uint32_t) into output (unsigned char). Assumes len is
			a multiple of 4.
			*/
			static void Encode(
				uint8_t           *output,
				const uint32_t       *input,
				const size_t  len )
			{
				size_t i=0, j=0;
				for(; j < len; i++, j += 4) {
					output[j]   = (uint8_t)(input[i] & 0xff);
					output[j+1] = (uint8_t)((input[i] >> 8) & 0xff);
					output[j+2] = (uint8_t)((input[i] >> 16) & 0xff);
					output[j+3] = (uint8_t)((input[i] >> 24) & 0xff);
				}
			}

			/* Decodes input (uint8_t) into output (uint32_t). Assumes len is
			a multiple of 4.
			*/
			static void Decode(
				uint32_t            *output,
				const uint8_t    *input,
				const size_t len
				)
			{

				size_t i=0,j=0;
				for(; j < len; i++, j += 4)
					output[i] = ((uint32_t)input[j]) | (((uint32_t)input[j+1]) << 8) |
					(((uint32_t)input[j+2]) << 16) | (((uint32_t)input[j+3]) << 24);
			}

			/* MD5 basic transformation. Transforms state based on block.
			*/
			static void MD5Transform (
				uint32_t      state[4],
				const uint8_t block[64]
			)
			{
				uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

				Decode(x, block, 64);

				/* Round 1 */
				FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
				FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
				FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
				FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
				FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
				FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
				FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
				FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
				FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
				FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
				FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
				FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
				FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
				FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
				FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
				FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

				/* Round 2 */
				GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
				GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
				GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
				GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
				GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
				GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
				GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
				GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
				GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
				GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
				GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
				GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
				GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
				GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
				GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
				GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

				/* Round 3 */
				HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
				HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
				HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
				HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
				HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
				HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
				HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
				HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
				HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
				HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
				HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
				HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
				HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
				HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
				HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
				HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

				/* Round 4 */
				II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
				II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
				II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
				II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
				II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
				II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
				II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
				II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
				II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
				II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
				II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
				II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
				II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
				II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
				II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
				II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

				state[0] += a;
				state[1] += b;
				state[2] += c;
				state[3] += d;

				/* Zeroize sensitive information.
				*/
				memset( x, 0, sizeof(x) );
			}

			/* MD5 initialization. Begins an MD5 operation, writing a new context.
			*/
			static void MD5Init( MD5_CTX *context )                                      /* context */
			{
				context->count[0] = context->count[1] = 0;
				/* Load magic initialization constants.
				*/
				context->state[0] = 0x67452301;
				context->state[1] = 0xefcdab89;
				context->state[2] = 0x98badcfe;
				context->state[3] = 0x10325476;
			}


			/* MD5 block update operation. Continues an MD5 message-digest
			operation, processing another message block, and updating the
			context.
			*/
			static void MD5Update(
				MD5_CTX        *context,                                        /* context */
				const uint8_t  *input,                                /* input block */
				size_t          inputLen                     /* length of input block */
				)
			{
				size_t i, index, partLen;

				/* Compute number of bytes mod 64 */
				index = (size_t)((context->count[0] >> 3) & 0x3F);

				/* Update number of bits */
				if ((context->count[0] += ((uint32_t)inputLen << 3))
					< ((uint32_t)inputLen << 3))
					context->count[1]++;
				context->count[1] += ((uint32_t)inputLen >> 29);

				partLen = 64 - index;

				/* Transform as many times as possible.
				*/
				if (inputLen >= partLen) {
					memcpy(&context->buffer[index], input, partLen);
					MD5Transform (context->state, context->buffer);

					for (i = partLen; i + 63 < inputLen; i += 64)
						MD5Transform(context->state, &input[i]);

					index = 0;
				}
				else
					i = 0;

				/* Buffer remaining input */
				memcpy( &context->buffer[index],  &input[i], inputLen-i);
			}

			/* MD5 finalization. Ends an MD5 message-digest operation, writing the
			the message digest and zeroizing the context.
			*/
			static void MD5Final (
				uint8_t  digest[16],                        /* message digest */
				MD5_CTX *context                                /* context */
				)
			{
				uint8_t bits[8];
				size_t index, padLen;

				/* Save number of bits */
				Encode(bits, context->count, 8);

				/* Pad out to 56 mod 64.
				*/
				index = (unsigned int)((context->count[0] >> 3) & 0x3f);
				padLen = (index < 56) ? (56 - index) : (120 - index);
				MD5Update(context, PADDING, padLen);

				/* Append length (before padding) */
				MD5Update(context, bits, 8);

				/* Store state in digest */
				Encode(digest, context->state, 16);

				/* Zeroize sensitive information.
				*/
				memset( context, 0, sizeof (*context));
			}

		} // RFC1321

		md5::md5() throw() : function(__length, __window), ctx()
		{
		}

		const char *md5:: name() const throw()
		{
			return "MD5";
		}


		void md5:: set() throw()
		{
			RFC1321::MD5Init( &ctx );
		}

		void md5:: run( const void *buffer, size_t buflen ) throw()
		{
			assert( !(buflen>0&&NULL==buffer) );
			RFC1321::MD5Update( &ctx, (const uint8_t *)buffer, buflen );
		}

		void md5::get(void *output, size_t outlen ) throw()
		{
			assert( !(output==NULL&&outlen>0) );
			uint8_t  digest[16];
			RFC1321::MD5Final( digest, &ctx );
			fill( output, outlen, digest, sizeof(digest) );
		}

		md5:: ~md5() throw()
		{
			memset( &ctx, 0 , sizeof(ctx) );
		}
	}

}
